Field of the Invention
The present invention relates to a reflective display device.
Discussion of the Related Art
Recently, with the advancement of the information age, display technology for processing and displaying large amount of information have rapidly developed. In response to this trend, various display devices have been introduced and spotlighted. Detailed examples of the display devices include liquid crystal display (LCD) devices, plasma display panel (PDP) devices, field emission display (FED) devices, electroluminescence display (ELD) devices, and organic light emitting display (OLED) devices.
Recently, the display devices have had properties of a thin profile, a light weight, and low power consumption, whereby application fields of the display devices have continuously increased. Particularly, the display device has been used as one of the user interfaces in most electronic devices and mobile devices.
Also, recently, many studies have been actively made for a reflective display device categorized into a reflective area and a display area. A reflective display device may be used as a mirror by reflecting light when an image is not displayed and serves as a general display device when an image is displayed.
In this case, however, since reflectance is not controlled while high reflectance is always maintained, the reflective display device cannot be properly operated as a display device because a contrast ratio is low when an image is displayed.
FIG. 1 is a brief view illustrating a conventional reflective display device.
As shown in FIG. 1, the conventional reflective display device includes a display area and a reflective area.
A thin film transistor T is formed on the display area, wherein the thin film transistor includes a first substrate 10, an active layer 11, a gate insulator 12, a gate electrode 13, a dielectric inter-layer 14, a source electrode 15, and a drain electrode 16, and a passivation layer 20 and a planarization layer 30 are formed on the thin film transistor T in due order.
An anode electrode 40 and an auxiliary electrode 50 are formed on the planarization layer 30. The auxiliary electrode serves to reduce resistance of a cathode electrode 80 which will be described later. A bank 60 is formed on the anode electrode 40 and the auxiliary electrode 50 to define a pixel area, an organic light emitting layer 70 is formed in the pixel area defined by the bank 60, and the cathode electrode 80 is formed on the organic light emitting layer 70.
A black matrix 91 and a color filter 92 are formed on a second substrate 90.
A reflective metal 93 is arranged on a reflective area of the second substrate 90. When an image is not displayed on the display area, the reflective metal 93 may serve as a mirror by reflecting light.
When Ag, Ag-alloys, and Al are used as the reflective metal 93 for high reflectance, however, a defect may occur due to low adhesion to the second substrate 90. Also, if an adhesive layer is added between the second substrate 90 and the reflective metal 93 in order to solve this problem, a color of reflected light might be changed due to thickness of the adhesive layer.
The related art described above is based on technical information owned by the inventor to derive the present invention or gained through the process of deriving the present invention, and is not necessarily known to the public prior to filing of the application of the present invention.